How Does Food Become Nutrition

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How Does Food Become Nutrition?

• Digestion and Indigestion
• Lecture 10
• February 25, 2008
• Dr. Hirsch

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Announcements

• Exam Thursday 2/28, Loree 022, 1235pm
• Please Bring 2 Pencil
• EARLY Diet Analysis submission
• 10 Points
• Correction, Dr. Hirsch email
• jbhirsch104_at_hotmail.com

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Digestive Tract
A long, muscular tube ? begins at the lips
? ends at the anus includes glands outside
the tube ? salivary glands ? liver ? gall
bladder ? pancreas
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GI Tract Big Hollow Tube
mouth

• Like one long continuous tube
• 30 feet long
• Operates outside the body

anus
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Digestion defined

• Digestion the process by which food and drink
  are broken down into their smallest parts for
  absorption so that the body can use them to build
  and nourish cells and to provide energy

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Digestion Bottom Line

• All about breakdown

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Macronutrient Breakdown
Carbohydrates
Simple sugars Monosaccharides Glucose, Fructose,
Galactose

• Protein

Amino Acids

• Fatty acids
• Glycerol
• Other glycerides

Fat (Lipids)
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2 Modes of Digestive Action

• Mechanical/Physical
• Chemical

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1. Mechanical Breakdown
Voluntary
Chewing
Mouth
Maceration, grinding, milling food into
homogeneous state
Churning up the food with digestive juices
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1b. Movement and Physiology

• Peristalsis
• Esophagus
• Stomach
• Intestines
• Emesis
• Diarrhea
• Constipation (Hemorrhoids)
• Flatulence

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2. Chemical Breakdown

• Inorganic Acids Base
• HCl (pH 2) Saliva (pH 7.4)
• Organic Enzymes -ases
• Carbohydrases
• amylase
• maltase, sucrase, lactase
• Proteases
• Lipases

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Question

• If the stomach is so acidic pH2, why doesnt
  it break itself down?

MUCUS coats and protects the intestinal lining
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Food and Health

• WHERE and HOW do we digest
• Carbohydrates
• Proteins
• Fats (Lipids)

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Carbohydrates

• Objective
• breakdown of large (starches) and small
  (disaccharides) carbohydrates into
  MONOsaccharides - GLUCOSE
• Where
• Mouth
• Stomach (to some extent)
• Small Intestine

glucose
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Proteins

• Objective
• breakdown to amino acids
• Where
• Stomach (to some extent)
• Small Intestine

amino acids
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Lipids (Fat)

• Objective
• breakdown to fatty acids and glycerol
• Where
• Mouth (very little)
• Stomach (to some extent)
• Small Intestine (MOST)

fatty acids
With the help of BILE
glycerol
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Timing Movement of Food
24 hours of Digestion

• Mouth Seconds
• Esophagus Seconds
• Stomach Up to 3 ½ hours
• Small Intestine Minutes
• Large Intestine Hours upon Hours

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Digestive System Detail
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Small Intestine Absorption
Once digested, food needs to be absorbed into the
blood to be transported around the body

• Happens diffusion, facilitated diffusion,
  osmosis, and active transport
• Need a lot of surface area!

http//www.schoolscience.co.uk/content/4/biology/a
bpi/digestion/digest6.html
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Intestine Absorption
Villi
MicroVilli
Epithilea
http//www.mrothery.co.uk/studentswork/student20p
resentations/271,11,Slide 11
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Role of Large Intestine

• Last stop in GI tract
• Recovery of water and electrolytes
• Formation and storage of feces
• Microbial fermentation to help digestion
• Over 500 species of bacteria

5 feet long 4 inches wide
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Liver

• Largest gland 500 functions
• Receives blood for processing
• Makes bile
• Filter
• removes harmful substances (e.g. wastes)
• Helps figure out how many nutrients will go to
  the rest of the body, and how many will stay
  behind in storage

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Bile
A complex fluid containing water, electrolytes
and organic molecules including bile acids,
cholesterol, phospholipids and bilirubin that
flows into the small intestine

• Facilitates absorption of fat and fat soluble
  vitamins in small intestine - acts as emulsifier
• Adult humans produce 400 to 800 ml daily
• Produced in liver
• Stored in gall bladder

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Controlling the Digestive System

• Digestive system has its own regulators
• Hormones
• control the functions of the digestive system
• produced and released by cells in the mucosa of
  the stomach and small intestine
• Stimulate digestive juices and cause organ
  movement

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Lowdown on Digestive System
Not Much
Alcohol Aspirin
Makes Bile Filters Blood
Hormones Enzymes
Stores Bile
Water Feces Fermentation
Enables Absorption of Mostly Everything Carbs P
roteins Lipids
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GI Disorders

• Heartburn/Indigestion
• GastroEsophageal Reflux Disease (GERD)
• Colorectal Cancer
• Constipation and Bloating

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Acid Indigestion Heartburn

• Backward flow of acid from the stomach up into
  the esophagus
• Feels like burning chest pain
• starts behind the breastbone
• moves up toward neck and throat

15 million Americans suffer per day 90 of
heartburn sufferers say it impacts their quality
of life http//www.acg.gi.org/patients/cgp/cgpvol1
.aspgerd
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How do you spell R E L I E F?

• Prescriptions
• block the acid pumps in the cells of the stomach
  at source
• Last 24 hours
• Over The Counter (OTC)
• reduce the amount of acid produced in the stomach
  
• Last 8-12 hours
• Antacids
• do not suppress acid production, partially
  neutralize existing acid
• Last 3 hours
• Food

• BIG BUSINESS!
• NEXIUM 3.3 BILLION
• PRILOSEC 200 400 MM
• PREVACID 3.2 BILLION
• Zantac
• Tums
• Rolaids
• DanActive

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Preventing GERDGastroEsophogeal Reflux Disease

• Avoid foods and beverages which may contribute
• chocolate, coffee, greasy or spicy foods, tomato
  products and alcoholic beverages.
• Avoid eating 2-3 hours before sleep
• Reduce weight if obese
• Stop smoking. Tobacco
• stimulates stomach acid production
• relaxes the muscle between the esophagus and the
  stomach
• Take an antacid, OTC or prescription

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Colorectal cancer

• Second most common cancer killer in the US
• Causes an estimated 55,000 deaths/year
• More than 138,000 new cases of colorectal cancer
  are diagnosed each year
• Men and women are equally affected

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Food for Gut Health

• Probiotics Live bacteria
• Improve intestinal microbial balance
• Yogurt live with active cultures
• Prebiotics Fiber
• Stimulate growth of beneficial bacteria in colon
• Inulin
• Polydextrose
• Resistant starch

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Probiotics
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Top 2007 Food Product Sales

• South Beach Diet 237MM
• Dreyers/Edys Slow Churned 229MM
• Breyers Double Churned 135MM
• Dannons Activia 128MM
• Coke Zero 121MM
• Gatorade Rain 120MM